LTC4270/LTC4271
TYPICAL PERFORMANCE CHARACTERISTICS
802.3af Power On Sequence in
AUTO Pin Mode
802.3at Power On Sequence in
AUTO Pin Mode
Power On Sequence with 10VPP
60Hz Noise
0
–10
–20
–30
–40
–50
–60
0
–10
–20
–30
–40
–50
–60
5
0
AGND
AGND
PORT OFF
FORCED VOLTAGE
DETECTION
AGND
FORCED CURRENT
DETECTION
FORCED CURRENT
DETECTION
–5
FORCED VOLTAGE
DETECTION
FORCED VOLTAGE
DETECTION
–10
–15
–20
–25
FORCED CURRENT
DETECTION
VEE = –55V
CLASS 4 PD
VEE = –55V
CLASS 3 PD
802.3af
CLASSIFICATION
802.3at
CLASSIFICATION
802.3af
CLASSIFICATION
POWER ON
50ms/DIV
POWER ON
VEE
VEE
DETECT WITH 60Hz NOISE
NORMAL DETECT
POWER ON
50ms/DIV
50ms/DIV
42701 G01
42701 G02
42701 G03
Classification Transient Response
to 40mA Load Step
Powering Up into a 180μF Load
VEE = –54V
Classification Current Compliance
0
AGND
V
DD
V
EE
= 3.3V
= –54V
–2
–4
40mA
PORT
CURRENT
20mA/DIV
PORT VOLTAGE
20V/DIV
–6
VEE
0mA
–8
LOAD FULLY CHARGED
–10
–12
–14
–16
–18
–20
PORT CURRENT
200mA/DIV
FOLDBACK
425mA
CURRENT LIMIT
PORT
VOLTAGE
1V/DIV
0mA
GATE VOLTAGE
10V/DIV
FET ON
–20V
VEE
0
10
20
30
40
50
60
70
50μs/DIV
5ms/DIV
CLASSIFICATION CURRENT (mA)
42701 G04
42701 G05
42701 G06
VDD Supply Current vs Voltage
VEE Supply Current vs Voltage
15.0
12.0
9.0
9.0
8.5
8.0
7.5
7.0
6.5
6.0
6.0
3.0
0.0
85°C
25°C
–40
85°C
25°C
–40
2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
–60
–50
–40
–30
–20
V
SUPPLY VOLTAGE (V)
V
SUPPLY VOLTAGE (V)
DD
EE
42701 G07
42701 G08
42701f
8
Linear [ Linear ]
